Injection system



Jan. 28, 1969 c. w. KINSLEY INJECTION SYSTEM Sheet of 2 Filed Nov. 8,1965 f INVENTOR. B/HARLES W. KlNsLEY E427 izq/28 Jan. 28, 1969 c. w.KlNsLl-:Y 3,424,154

INJECTION SYSTEM Filed Nov. 8, 1965 sheet 2 of 2 United States Patent OClaims ABSTRACT OF THE DISCLOSURE A system for injecting liuids, such aslocal anesthetic liquids, into the soft tissues, particularly the gums,of a living body comprising a hand piece having a probe terminating in ajet orifice from which a high-velocity jet of liquid may be ejected froman ampule within the hand piece by movement of a piston within the handpiece and actuated by a liquid column in a ilexible tube connected to aremote pneumatic motor. In the preferred form, the pneumatic motorincludes a major piston and an auxiliary piston spring urged away fromsaid major piston but movable, under the inlluence of pressure flow, tostrike a hammer blow against said major piston in the direction ofliquid-ejecting motion of said major piston, to start said major pistonin such motion.

The present invention relates to a system for injecting fluids into thesoft tissues of a living body without the use of a solid instrument forpuncturing the skin. The principle of this type of injection has been inuse for several years and its effectiveness for the hypodermic placementof anesthetics, medicaments and the like is recognized. However,apparatus for accomplishment such injection,

which is usually referred to as jet injection has heretofore been heavy,cumbersome, difficult to apply in restricted regions, expensive toproduce and not well adapted to maintenance in reasonably sterilecondition.

Because of the awkwardness of previously known apparatus, and because ofother characteristics thereof, the principle of jet injection has notbeen applied to dental anesthesia, so far as I know, except in oneseries of experiments conducted under the Iauspices of the United StatesArmed Forces and reported in the United States Armed Forces MedicalJournal, volume IX No. 5, dated May 1958. In that series of experiments,the basic principlesof previously-known apparatus for jet injection wereused, the only signicant modification being the provision of anelongated and bent probe attached to the main housing of such knownapparatus. So far as I am advised, although those experiments werereasonably successful, they have not since been extended and theprinciple of jet injection has not been adopted at all by the dentalprofession.

Among the disadvantages of previously-known apparatus for jet injectionis the fact that such apparatus has universally depended upon heavysprings, pre-stressed by suitable winding means and trigger-released, todrive piston means for applying pressure and motive force to eject afluid, through a restricted orifice, to accomplish the injection.Inevitably, when the spring-driven piston reachesthe end of its strokein such apparatus, at least a slight mechanical blow is delivered to thebody of the apparatus; and since the apparatus is necessarily in contactwith the patient, the patient will feel some physical shock. If the siteof the injection is a patients jaw, even a slight mechanical shock ishighly objectionable. The fall of the piston also necessarily producessome noise; and, again, if A'the apparatus is in contact with thepatients jaw, that noise will be exaggerated in the patients hearing.

Among the objects of the present invention is the provision of jetinjection apparatus in which motive force is 3,424,154 Patented Jan. 28,1969 lCe applied to the fluid for injection through iluid motor means,in which the probe, the medicament-contalnmg ampule and the pistondirectly associated with the ampule may be assembled in a small, light,readily-manipulable housing and that housing may be physically remotefrom the prime mover through which power is applied to the said piston.In its optimum form, the above mentioned assembly will be operativelyconnected to the prime mover through a flexible tube in which iscontained a liquid column through which motion of the prime mover istransmitted to the piston element of the said assembly.

A further object of the invention is to provide apparatus of thecharacter described in which all of the apparatus except the small,above mentioned 'assembly may be screened from the vision of thepatient. A still further object of the invention is to provide suchapparatus in which the prime mover will not deliver a physical shock tothe hand-held assembly, in which the noise resulting from operation ofthe prime mover will not ibe transmitted to the hand-held unit and inwhich the patient will not be subjected either to physical shock or toexaggerated noise transmitted to his cranial bone structure through theprobe Another object of the invention is to provide jet injectionapparatus which is devoid of springs, which is simple and inexpensive inconstruction and in which the portions which must be brought into closecontiguity to the patient may be readily dismounted for easysterilization.

Still another object of the invention is to provide a novel ampule forcontaining the fluid to be injected, the particular construction of saidampule adapting it for highly advantageous use in the apparatus hereindisclosed.

Still further objects of the invention will appear as the descriptionproceeds.

To the accomplishment of the above and related 0bjects, my invention maybe embodied in the forms illustrated in the `accompanying drawings,attention being called to the fact, however, that Vthe drawings areillustrative only, 'and that change may be made in the specilicconstructions illustrated and described, so long as the scope of theappended claims is not violated.

FIG. 1 is a more or less diagrammatic illustration of a system embodyingthe present invention;

FIG. 2 is an enlarged, longitudinal section through a portion of thehand-held assembly forming a feature of the invention, and illustratinga novel ampule in place for use in the system;

FIG. 3 is a further-enlarged, fragmentary section illustrating detailsof construction of the distal end portion of la probe constituting anelement of the invention, shown in use position and illustrating themode of cooperation of the probe end with the soft tissues of thepatient, in a somewhat idealized form;

FIG. 4 is an enlarged, axial section through the lluid motorconstituting the prime mover of the system of the present invention; and

FIG. 5 is a section of the distal end portion of a modilied form ofprobe.

Referring more particularly to the drawings, it will be seen that I haveillustrated a tubular body 10, open at both ends and formed Iat one endwith a reduced, externally threaded extension 11. A tubular probe isindicated generally by the reference numeral 12 and comprises a shank ordistal portion 13 and an enlarged base 14 formed at its proximal endwith a socket 15 having an internally threaded extension 16 forcooperative engagement with the extension 11 of the body 10. The probeis formed with an axial bore 17 in which is received, with an easy pushiit, a hollow tube 18.

Advantageously, the hollow tube 18 maybe essentially a conventionalhypodermic needle whose Ibore 19 is of the desired diameter, but whoseunsharpened end has been spun down or tapered as at 20 to define aminute orifice 21. Such a needle is conventionally provided with a fixedbead 22 and the socket 15 is desirably formed with a seat 23 againstwhich the bead 22 abuts to limit movement of the tube toward the distalend of the probe shank 13. It will be perceived that, when the bead isso seated, the sharpened end 24 of the needle '18 is disposed within thesocket 15 at a predetermined axial position and for a reason which willappear.

An ampule for use in the assembly is indicated generally by thereference numeral 25. It comprises a body 26 proportioned and designedfor snug reception in the tubular body 10, and a neck 27 of reduceddiameter adapted to extend beyond the open end of the reduced extension11. The neck 27 is closed by a penetrable diaphragm 28, such as arubberoid stopper, held in place by a preferably metal collar 29externally gripping the neck of the ampule and centrally formed with aperforation 30. It will be readily perceived that, when the ampule ispositioned in the body 1()` and when the probe base 14 is moved by thecoaction of the threads 11 and 16 to bring the socket 15 intocommunicating registry with the open end of the body 10, the sharpenedend 24 of the needle '18 will penetrate the diaphragm 28 to enter theinterior of the ampule and the base of the socket 1S will bear upon thecollar 29 to hold the ampule positively against movement toward the leftas viewed in FIG. 2.

The opposite end of the ampule is closed by a stopper 31 which isdesigned and intended to act as a piston Within the ampule, movabletoward the left to eject the contents of the ampule through the needle18. The piston 31 is formed of material which is resilientlytransaxially compressible, and its equilibrium diameter somewhat exceedsthe internal diameter of the ampule body 26. Preferably, the forward ordistal end of the piston 31 is formed with a reduced extension 34 whosediameter is slightly less than the internal diameter of the ampule neck27, and that extension is circumscribed by an annular groove 35 defininga forwardly-tapered annular lip 36. The piston 31 is inserted in therear end of the ampule by peripherally contracting the lip 36, enteringthe lip in the ampule end, and then forcing the piston toward the left,as viewed in FIG. 2, until the major portion of the length of the pistonis enclosed Within the ampule body, but a minor portion 32 of thepistons length remains outside the ampule body. As the piston is soentered in the ampule body, of course it will be transaxiallycompressed, while the portion 32 will retain its equilibrium diameter.As a consequence, when the piston reaches its illustrated positionrelative to the ampule body, its proximal end portion 32 will define aperipheral lip 33 overhanging the proximal end of the ampule body; andthat lip will offer a significant degree of resistance to furthermovement of the piston 31 toward the left relative to the ampule body.

A piston 37, having an elongated stem or plunger 38, is reciprocablymounted in the tubular body behind the ampule 25, said stem preferablybeing guided in an annular bearing 39 within the length of the body 10,and the body being provided with one or more vent ports 40 just to therear of said shoulder so that pressure cannot build up within the bodybetween the head of the piston 37 and the ampule 25. As is most clearlyillustrated in FIG. 2, the distal end of plunger 38 has a diameterslightly smaller than the internal diameter of the ampule body 26, andis constructed and arranged to bear atly against the proximal end of thepiston 31.

Suitable coupling means 41 connects the open proximal end of the body 10through a iiexible tube 42 to a T-fitting 43 which, in turn, isconnected by conduit means 44 to an elongated chamber 45. The chamber45, as shown, is formed with an annular, internal step or shoulder 46upon which is supported a liner 47, suitable packing means 48 beingcarried between the liner and the shoulder 46. A third piston 49 isreciprocably received in the liner 47.

Suitable coupling means 50 connects the upper end of the chamber 45 withthe bottom head 51 of a pneumatic motor indicated generally by thereference numeral 52. An open ended cylinder 53 has one end closed bythe head 51 and has its other end closed by an upper head 54 to define achamber 55 which is entered by the stem 56 of the piston 49; and withinsaid chamber 55, said stern carries a fourth piston 57 which ispenetrated by one or more axially extending ports 58 and which is muchlarger in effective diameter than the pistons 49 and 37. A headed guidepin 59 is fixed to said fourth piston 57 and limits the path of travel,relative to the piston 57, of a fifth piston 60, a coiled spring 61being confined between the pistons 57 and 60 to urge the piston 60 awayfrom the piston 57.

The head 51 is formed with a port 62 to Which is connected a branch pipe63, and the head 54 is formed With a port -64 to which is connected abranch pipe 65 for purposes which will appear.

In FIG. 4, the assembly comprising the pistons 49, 57 and 60, the stem56 and the pin 59, is shown in its normal, retracted position, with thepistons 60 and 57 fully separated. The cylinder 53 is formed with a port66 at a level which, when the said assembly is so retracted, registerswith the space between the pistons 57 and 66. The reduced neck 67 of avalve housing 68 is threadedly received in the port 66. Said housing isformed to provide an internal seat 69 with which cooperates a valvemember 70 yieldably held in closing contact with said seat by a coiledspring 71 confined between said valve member and an adjustable screw 72threadedly received in that end of the housing 68 remote from the neck67. It will be apparent that adjustment of the screw 72 will vary theeffective force with which the spring 71 urges the valve member againstthe seat 69. A jam nut 73 may be provided to retain the screw 72 in anyselected position of adjustment. An exhaust port 74 opens from theinterior of the housing 68 to atmosphere.

A conduit 75 leads from a source (not shown) of air under pressure to aT-fitting 76 with which is connected an accumulator chamber 77, apressure gauge 77' being in communication with said chamber. A pipe 78leads from the fitting 76 to the inlet port 79 of a conventionalfour-Way valve 80 having one delivery port 81 to which is connected thebranch pipe 63 and a second delivery port I82 to which is connected thebranch pipe 65. To the exhaust port 83 of the valve 80 is preferablyconnected a pipe 85 leading to a muier 86. Conventional solenoidprogramming means for the valve 80 is indicated at 84.

From the T-litting 43 extends a pipe 87 with which communicates apressure gauge 88, and said pipe leads, through a check valve 89, to amanually-operable pump connected to a liquid reservoir 91. The pump 90is operable to establish a continuous column of liquid within the tube42, the tubular body 10 and the elongated chamber 45, providing anairmative motion-transmitting link between the piston 49 and the piston37; and it will be seen that said pump is further operable to establisha predetermined degree of pressure within said column.

In FIG. 3, I have illustrated what I presently consider to be an optimumform for the distal end face 92 of the probe 13. As shown, said end face92 is formed with a central, outwardly flaring cavity 93 within which isdisposed the tip of the needle 18 defining the jet orifice 21, said tipbeing substantially flush with the transaxial surface 92. The cavity 93is circumscribed by an annular groove 94. Thus, when the probe face 92is pressed against a region 95 of the soft tissues of a living body, ittends to establish a mound 96 protruding into the cavity 93 andcentrally depressed by the tip 20 of the needle; and it tends toestablish, as well, an annular mound 97 surrounding the mound 96. Thus,substantial normality of the axis of the tip region of the needle 18relative to the surface of the tissues engaged by the needle tip isassured; and this is important because it has been discovered thatunless such normality is maintained, the issuing jet of liquid is likelyto lacerate the tissues instead of establishing the desired rectilinearchannel within the tissues.

In FIG. 5, I have illustrated a fragment of a modified form of probe 12in which the shank 13' is bent to facilitate the location of its tip 92'in a restricted region. Needles 18 of the character above described arequite flexible, and I have found that a needle 18 can `be inserted inthe bore 17 of such a probe without difficulty.

It is known that, for optimum practice of jet injection,

the initial portion of the jet stream, which is to accomplish thedrilling, tissue-penetration or opening of a channel to a desired depthbeneath the skin must be moving at extremely high velocity, andtherefore under maximum pressure. This penetrating stream should befollowed by an abrupt pressure decay to a much lower velocity wherebythe following liquid may flow into the channel so defined and maydisperse radially through the tissue layers, primarily near the bottomof the channel which has thus been prepared by the initial pressurestream. As the injection nears completion, the pressure and velocity ofthe stream should again drop sharply to zero. While quantitativepressure and velocity values cannot be specically prescribed, it can besaid that, in most cases, the pressure program which starts at zerop.s.i. should climb almost instantaneously to a maximum of, forinstance, 8000 p.s.i. for drilling, should then fall off steeply toperhaps 3,000 p.s.i. for injection and dispersal of the main charge andthen should fall off steeply to zero p.s.i. at the end of the injectioncycle.

In an apparatus of the character here under consideration, pressure andvelocity through a given orifice bear a direct relationship to eachother and therefore it can be seen that regulation of the pressure whichis brought to bear on the injection iiuid (upstream from the orifice)will determine the velocity of injection and thus the depth of thechannel and the amount of dispersal of the following liquid charge. Theapparatus herein disclosed inherently will operate to accomplish thepressure program above described as optimum.

Operation The apparatus is designed primarily for use with forty poundair pressure which is available in most dental offices and in theoffices of many physicians; but of course it will be understood that, byadaptations which will be obvious to those skilled in the art, the Huidmotor 52 could be supplied from pressure cylinders or in any other way.When the apparatus is to be used, the probe 12 will be removed from thetubular body and an ampule 25 containing the proper volume of the fluidto be injected will be inserted through the thus-opened end of thetubular body 10. The ampule is so proportioned and designed that, whenits piston 31 is pressed against the distal end of the retracted pistonstem 38, the ampule neck will project beyond the open end of the body10. Now, the probe 12 is mounted on the body 10 by threading theextensions 16 and 11 together, and as the extension 16 approaches itsseat, the sharpened end 24 of the needle 18 will pass through the port30 in the collar 29 and will penetrate the diaphragm 28, thus openingthe interior of the needle 18 to the contents of the ampule 25.

The column of liquid between the pistons 49 and 37, once established,will normally be maintained at all times. Just before the apparatus isto be used, the plunger of the pump 90 will be depressed a few times inorder to prepressurize that column or hydraulic link to approximately 1to 2 p.s.i. as indicated on the gauge 88 in order to be certain that thehydraulic link is solid throughout the system so that the movement ofthe piston 37 shall certainly be directly proportional to the movementof the piston 57. The lip 33 of the piston 31 provides sufficientresistance to leftward movement of the piston to retain aid pistonagainst such pre-pressurizaiton of the hydraulic ink.

The normal or rest condition of the valve is such as to retain thepiston assembly 57-60 in its illustrated position. The operator nowplaces the distal face 92 of the probe 12 or 12 in proper positionagainst the tissue to be injected, and trips a trigger (not shown) whichactuates the control 84 to dump compressed air from the accumulator tank77 through the branch pipe 65 into the upper end of the cylinder 53.Instantly, the fifth piston 60 is forced downward with an acceleratingvelocity, against the tendency of the spring 61, toward the upper faceof the fourth piston 57. Air entrapped between the pistons 60 and 57, ofcourse, ows freely through the ports 58 and thence through the branchpipe 63 to be discharged through the exhaust pipe 85. By the time thepiston 60 comes into contact with the piston 57, the piston 60 is movingat high velocity and its mass transmits a heavy initial hammer blow tothe piston 57. If desired, the contacting surfaces of the pistons 60 and57 may be cushioned with a nylon or Teflon pad to reduce the noise ofcontact. The hammer blow, of course, moves the piston 49instantaneously, but through a very short distance, at extremely highvelocity; and movement of the piston 49, of course, is transmittedthrough the -hydraulic link to the piston 37 and thence to the piston 31so that a jet of the fluid contained in the ampule 25 will be emitted atextremely high velocity through the minute orifice 21 to drill thedesired channel in the tissues 95.

If, for instance, the effective area of the pistons 60` and 57 has a twoinch diameter while the pistons 49 and 38 have one-quarter inchdiameters, a pressure of 40 p.s.i. on the pistons 60 and 57 will bemultiplied to approximately 8000 p.s.i. delivered to the piston 31; andof course the initial starting pressure exerted on the piston 31 will beconsiderably higher than that because of the inertial effect of theimpact of the piston 60 upon the piston 57.

After the piston 60 has thus delivered its hammer blow to the piston 57,the two pistons will continue to move downwardly to force followingportions of the contents of the ampule 25 to enter the channel definedin the soft tissues. Momentarily thereafter, the upper end of the piston60 will clear the port 66 whereby a metered escape of a portion of theincoming air past the valve 70 will be established to assist in reducingthe velocity of travel of the piston assembly, thus controlling the rateof decay of the velocity of discharge of the contents of the ampule.

During travel of the piston 31, of course, the lip 36 is forciblypressed against the internal wall of the ampule to inhibit escape of theuid past the piston. The provision of the reduced extension 34, whichwill enter the ampule neck 27 at the end of the piston stroke, providesfor maximum use of the contents of the ampule. It is not intended,however, that the extension 34 shall have a uid tight fit in the ampuleneck; and the lip 36 will engage the shoulder of the ampule at the baseof the neck to stop piston movement before the extension 34 can comeinto contact with the sharpened end 24 of the needle 18.

Preferably, the control 84 for the valve 80 will be of such -characterthat, upon completion of the stroke of the piston 31, the valve 80 willbe actuated to connect the pressure supply to the branch pipe 63 andconnect the branch pipe 65 to exhaust, whereby the pistons 57 and 60will be lifted. Such movement, of course, will be accompanied byretraction of the piston 37, whereupon the probe 12 may be disconnectedfrom the body 10, the ex- -hausted a-mpule may be removed and a newampule may be inserted if the mechanism is to be promptly used again.

I claim as my invention:

1. A system for injecting fluids into the soft tissues of a living body,said system comprising a tubular body provided at one end with a probeformed with an axial orifice, an ampule containing a fluid to beinjected, said ampule being received in said body in communication withsaid orifice, a first piston closing that end of said ampule remote fromsaid orifice and movable toward said orifice to eject such Huid throughsaid orifice, a second piston reciprocably received in said body andbearing axially on said first piston, a flexible tube having one endconnected to the other end of said body, an elongated chamber connectedto the other end of said tube, a third piston reciprocably mounted insaid chamber, a column of liquid in said flexible tube providing adriving connection between said third piston and said second piston, anda pneumatic motor operatively connected to drive said third pistontoward said tubular body, said pneumatic motor comprising a cylinder, afourth piston reciprocably mounted in said cylinder, operativelyconnected to said third piston and having anetfective diametersignificantly exceeding that of said lirst piston, a fifth pistonreciprocably mounted in said cylinder and yieldably separated from saidfourth piston in a direction remote from said third piston, said motorbeing formed to provide open communication between opposite sides ofsaid fourth piston except when said fifth piston substantially engagessaid fourth piston, and said cylinder being provided with an inlet portat a point more remote from said third piston than is said fifth pistonand with an outlet port at a point between said fourth piston and saidthird piston.

2. The system of claim 1 in which said fourth piston is axially portedto provide such open communication.

3. The system of claim 1 including a source of pneumatic liuid underpressure, conduit means connecting said source with said inlet port, andvalve means disposed in said conduit means and controlling communicationbetween said source and said inlet port.

4. The system of claim 1 in which said cylinder is provided with a bleedport normally located between said fourth piston and `said fifth piston,said bleed port providing communication between the atmosphere and theinterior of said cylinder only when said fourth and fifth pistons havebeen advanced.

5. The system of claim 4 including adjustable Valve means associatedwith said bleed port to control the effective flow capacity of saidvbleed port.

References Cited UNITED STATES PATENTS Re. 19,219 6/1934 Smith 128-218-12,547,099 4/1951 Smoot 128--173 2,688,325 9/1954 Lockhart 128-2182,604,757 7/1952 Wulleman 60-54.5 2,669,230 2/1954 Smoot 128-1732,904,043 9/1959 Friedman 12S-218.1 3,189,029 6/1965 Stephens 128-1733,059,433 10/1962 Hirsch 60-54.5

RICHARD A. GAUDET, Primary Examiner.

KYLE L. HOWELL, Assistant Examiner.

U.S. Cl. X.R. 12S-218; 60-54.5

